Evolution of the radio access scheme and the radio network for cellular mobile communication (LTE (Long Term Evolution) or EUTRA (Evolved Universal Terrestrial Radio Access)) has been specified by the 3rd Generation Partnership Project (3GPP). LTE uses, as a communication scheme for downlink radio communication (also referred to as “DL”) from a base station device to a mobile station device, the Orthogonal Frequency Division Multiplexing (OFDM) scheme which is a multicarrier transmission scheme. LTE also uses, as a communication scheme for uplink radio communication (also referred to as “UL”) from a mobile station device to the base station device, the SC-FDMA (Single-Carrier Frequency Division Multiple Access) scheme which is a single-carrier transmission scheme. LTE uses the DFT-Spread OFDM (Discrete Fourier Transform-Spread OFDM) scheme as the SC-FDMA scheme.
The 3GPP has studied a radio access scheme and a radio network that use a broader frequency band than LTE to implement still faster data communication (LTE-A (Long Term Evolution-Advanced) or A-EUTRA (Advanced Evolved Universal Terrestrial Radio Access)). LTE-A is required to have backward compatibility with LTE. Specifically, LTE-A is required to meet the requirement that a base station device conforming to LTE-A should communicate with both a mobile station device conforming to LTE-A and a mobile station device conforming to LTE simultaneously, and the requirement that a mobile station device conforming to LTE-A should communicate with the base station device conforming to LTE-A and a base station device conforming to LTE. In order to meet these requirements, it has been studied for LTE-A to at least support the same channel structure as that of LTE. “Channel” means a medium used for signal transmission. There are different types of channels including, for example, Physical Downlink Shared CHannel (PDSCH) used for transmitting/receiving downlink data, Physical Downlink Control CHannel (PDCCH) used for transmitting/receiving downlink control information, Physical Uplink Shared CHannel (PUSCH) used for transmitting/receiving uplink data and uplink control information, Physical Uplink Control CHannel (PUCCH) used for transmitting/receiving uplink control information, Synchronization CHannel (SCH) used for establishing downlink synchronization, Physical Random Access CHannel (PRACH) used for establishing uplink synchronization, and Physical Broadcast CHannel (PBCH) used for transmitting downlink system information.
Regarding LTE-A, a technology of using multiple frequency bands (component carriers (CC)) of the same channel structure as that of LTE, as one frequency band (wider frequency band). This technology is also referred to, for example, as spectrum aggregation, carrier aggregation, or frequency aggregation.
Specifically, in the communication using this technology, each component carrier of downlink (hereinafter referred to as “downlink component carrier”) transmits/receives a downlink channel, and each component carrier of uplink (hereinafter referred to as uplink component carrier) transmits/receives an uplink channel. Namely, carrier aggregation is a technology allowing a base station device and a mobile station device to simultaneously transmit/receive signals on multiple channels, using multiple component carriers for uplink and downlink. Here, “downlink component carrier” is also referred to as “DL CC” and “uplink component carrier” is also referred to as “UL CC.”
A mobile station device uses the physical uplink control channel to transmit control information (receipt acknowledgement: ACK/NACK) indicating acknowledgement (ACK) or negative acknowledgement (NACK)) in response to data received using the physical downlink shared channel. The base station device controls retransmission of the physical downlink shared channel based on the receipt acknowledgement received from the mobile station device. According to LTE-A using the carrier aggregation, the base station device can simultaneously use multiple physical downlink shared channels to transmit data to a mobile station device. The mobile station device receiving multiple physical downlink shared channels by means of the carrier aggregation must inform the base station device of multiple receipt acknowledgements simultaneously. As for LTE, the base station device can simultaneously use only one physical downlink shared channel to transmit data to a mobile station device. The mobile station device receiving one physical downlink shared channel uses the physical uplink control channel to inform the base station device of one receipt acknowledgement. Regarding LTE-A, it has been studied to introduce a physical uplink control channel of a new signal configuration for allowing a mobile station device to transmit multiple receipt acknowledgements to the base station device. Specifically, it has been studied to introduce a physical uplink control channel using the DFT-S-OFDM scheme.
In LTE-A, it has been studied to allow a mobile station device to transmit, using the physical uplink control channel, control information (scheduling request: SR) indicating a request for uplink resource allocation, like LTE. As also disclosed in NPL 1 referenced below, it has been studied in LTE-A, in order for a mobile station device to simultaneously transmit multiple receipt acknowledgements and the scheduling request, (i) to allow the mobile station device to perform common coding (joint coding) on information bits including information bits of multiple receipt acknowledgements and information bits of the scheduling request, (ii) to allow the mobile station device to modulate the coded bits, and (iii) to allow the mobile station device to transmit a modulation symbol on the physical uplink control channel using the DFT-S-OFDM scheme.